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From 8a68e0a6f3a62c3e382791774e5feb9506e1f7d8 Mon Sep 17 00:00:00 2001
From: Justus Winter <4winter@informatik.uni-hamburg.de>
Date: Wed, 15 Jul 2015 15:11:05 +0200
Subject: [PATCH gnumach 1/2] ipc: fix the locking of the IPC entry allocation
functions
* ipc/ipc_entry.c (ipc_entry_alloc): Assume the space is write-locked.
(ipc_entry_alloc_name): Likewise.
* ipc/ipc_object.c: Fix the locking around all call sites to the two
functions where the space was not locked before.
---
ipc/ipc_entry.c | 21 ++-------------------
ipc/ipc_object.c | 32 ++++++++++++++++++++------------
2 files changed, 22 insertions(+), 31 deletions(-)
diff --git a/ipc/ipc_entry.c b/ipc/ipc_entry.c
index a5fe319..0414ba5 100644
--- a/ipc/ipc_entry.c
+++ b/ipc/ipc_entry.c
@@ -56,8 +56,7 @@ struct kmem_cache ipc_entry_cache;
* Purpose:
* Allocate an entry out of the space.
* Conditions:
- * The space is not locked before, but it is write-locked after
- * if the call is successful. May allocate memory.
+ * The space must be write-locked. May allocate memory.
* Returns:
* KERN_SUCCESS An entry was allocated.
* KERN_INVALID_TASK The space is dead.
@@ -75,27 +74,21 @@ ipc_entry_alloc(
ipc_entry_t entry;
rdxtree_key_t key;
- is_write_lock(space);
-
if (!space->is_active) {
- is_write_unlock(space);
return KERN_INVALID_TASK;
}
kr = ipc_entry_get(space, namep, entryp);
if (kr == KERN_SUCCESS)
- /* Success. Space is write-locked. */
return kr;
entry = ie_alloc();
if (entry == IE_NULL) {
- is_write_unlock(space);
return KERN_RESOURCE_SHORTAGE;
}
kr = rdxtree_insert_alloc(&space->is_map, entry, &key);
if (kr) {
- is_write_unlock(space);
ie_free(entry);
return kr;
}
@@ -108,7 +101,6 @@ ipc_entry_alloc(
*entryp = entry;
*namep = (mach_port_t) key;
- /* Success. Space is write-locked. */
return KERN_SUCCESS;
}
@@ -118,8 +110,7 @@ ipc_entry_alloc(
* Allocates/finds an entry with a specific name.
* If an existing entry is returned, its type will be nonzero.
* Conditions:
- * The space is not locked before, but it is write-locked after
- * if the call is successful. May allocate memory.
+ * The space must be write-locked. May allocate memory.
* Returns:
* KERN_SUCCESS Found existing entry with same name.
* KERN_SUCCESS Allocated a new entry.
@@ -138,10 +129,7 @@ ipc_entry_alloc_name(
void **slot;
assert(MACH_PORT_VALID(name));
- is_write_lock(space);
-
if (!space->is_active) {
- is_write_unlock(space);
return KERN_INVALID_TASK;
}
@@ -152,7 +140,6 @@ ipc_entry_alloc_name(
if (slot == NULL || entry == IE_NULL) {
entry = ie_alloc();
if (entry == IE_NULL) {
- is_write_unlock(space);
return KERN_RESOURCE_SHORTAGE;
}
@@ -167,7 +154,6 @@ ipc_entry_alloc_name(
kr = rdxtree_insert(&space->is_map,
(rdxtree_key_t) name, entry);
if (kr != KERN_SUCCESS) {
- is_write_unlock(space);
ie_free(entry);
return kr;
}
@@ -175,14 +161,12 @@ ipc_entry_alloc_name(
space->is_size += 1;
*entryp = entry;
- /* Success. Space is write-locked. */
return KERN_SUCCESS;
}
if (IE_BITS_TYPE(entry->ie_bits)) {
/* Used entry. */
*entryp = entry;
- /* Success. Space is write-locked. */
return KERN_SUCCESS;
}
@@ -202,7 +186,6 @@ ipc_entry_alloc_name(
space->is_size += 1;
*entryp = entry;
- /* Success. Space is write-locked. */
return KERN_SUCCESS;
}
diff --git a/ipc/ipc_object.c b/ipc/ipc_object.c
index 2d84cf5..320fbcb 100644
--- a/ipc/ipc_object.c
+++ b/ipc/ipc_object.c
@@ -155,11 +155,12 @@ ipc_object_alloc_dead(
ipc_entry_t entry;
kern_return_t kr;
-
+ is_write_lock(space);
kr = ipc_entry_alloc(space, namep, &entry);
- if (kr != KERN_SUCCESS)
+ if (kr != KERN_SUCCESS) {
+ is_write_unlock(space);
return kr;
- /* space is write-locked */
+ }
/* null object, MACH_PORT_TYPE_DEAD_NAME, 1 uref */
@@ -191,11 +192,12 @@ ipc_object_alloc_dead_name(
ipc_entry_t entry;
kern_return_t kr;
-
+ is_write_lock(space);
kr = ipc_entry_alloc_name(space, name, &entry);
- if (kr != KERN_SUCCESS)
+ if (kr != KERN_SUCCESS) {
+ is_write_unlock(space);
return kr;
- /* space is write-locked */
+ }
if (ipc_right_inuse(space, name, entry))
return KERN_NAME_EXISTS;
@@ -254,12 +256,13 @@ ipc_object_alloc(
memset(pset, 0, sizeof(*pset));
}
+ is_write_lock(space);
kr = ipc_entry_alloc(space, namep, &entry);
if (kr != KERN_SUCCESS) {
+ is_write_unlock(space);
io_free(otype, object);
return kr;
}
- /* space is write-locked */
entry->ie_bits |= type | urefs;
entry->ie_object = object;
@@ -321,12 +324,13 @@ ipc_object_alloc_name(
memset(pset, 0, sizeof(*pset));
}
+ is_write_lock(space);
kr = ipc_entry_alloc_name(space, name, &entry);
if (kr != KERN_SUCCESS) {
+ is_write_unlock(space);
io_free(otype, object);
return kr;
}
- /* space is write-locked */
if (ipc_right_inuse(space, name, entry)) {
io_free(otype, object);
@@ -753,10 +757,12 @@ ipc_object_copyout_name(
assert(IO_VALID(object));
assert(io_otype(object) == IOT_PORT);
+ is_write_lock(space);
kr = ipc_entry_alloc_name(space, name, &entry);
- if (kr != KERN_SUCCESS)
+ if (kr != KERN_SUCCESS) {
+ is_write_unlock(space);
return kr;
- /* space is write-locked and active */
+ }
if ((msgt_name != MACH_MSG_TYPE_PORT_SEND_ONCE) &&
ipc_right_reverse(space, object, &oname, &oentry)) {
@@ -930,10 +936,12 @@ ipc_object_rename(
ipc_entry_t oentry, nentry;
kern_return_t kr;
+ is_write_lock(space);
kr = ipc_entry_alloc_name(space, nname, &nentry);
- if (kr != KERN_SUCCESS)
+ if (kr != KERN_SUCCESS) {
+ is_write_unlock(space);
return kr;
- /* space is write-locked and active */
+ }
if (ipc_right_inuse(space, nname, nentry)) {
/* space is unlocked */
--
2.1.4
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